A new family of bioactive iron calcium phosphate glasses will be evaluated as thermoseeds for hyperthermia of cancers, especially bone tumors. Through appropriate heat treatment and atmosphere control, the Fe3+/Fe2+ ratio can be adjusted to achieve the desired magnetic hysteresis. The heat generating characteristics of these glasses under external magnetic induction will be studied as a function of glass composition, processing, sample geometry and microstructure. One or more candidate glass compositions will be identified for use in Phase II study where such material will be used in various in vitro, in vivo evaluations. Glass composition formulation takes into account of magnetic properties, bioactivity and glass forming characteristics. An appropriate balance among these properties will make such glass ideal as filler to bone defects after curettage of bone tumors, as filler in bone cements, etc. at the same time it is used as thermoseeds. In addition, iron calcium phosphate glasses can be made resorbable.